c++ 常用的一些字符转换

wstring string_to_wstring( string& s ){ if( s.empty() ) return _T("");  int retval = ::MultiByteToWideChar(CP_ACP,0,s.c_str(),s.size(),0,0); wstring re; re.resize( retval ); ::MultiByteToWideChar(CP_ACP,0,s.c_str(),s.size(),&re[0],re.size()); return re;}/// 宽字符串 到 一般窄字符串string wstring_to_string( wstring& ws ){   if( ws.empty() ) return "";   int retval = ::WideCharToMultiByte(CP_ACP,0,ws.c_str(),ws.size(),0,0,0,0);   string re;   re.resize( retval );   ::WideCharToMultiByte(CP_ACP,0,ws.c_str(),ws.size(),&re[0],re.size(),0,0);   return re;}/// 宽字符串 到 一般窄字符串string wstring_to_string( wchar_t* ws, size_t sz ){   if( ws == NULL || sz == 0 ) return "";   int retval = ::WideCharToMultiByte(CP_ACP,0,ws,sz,0,0,0,0);   string re;   re.resize( retval );   ::WideCharToMultiByte(CP_ACP,0,ws,sz,&re[0],re.size(),0,0);   return re;}/// 窄字符串 到 宽字符串wstring utf8_to_wstring( string& s ){   if( s.empty() ) return _T("");    int retval = ::MultiByteToWideChar(CP_UTF8,0,s.c_str(),s.size(),0,0);   wstring re;   re.resize( retval );   ::MultiByteToWideChar(CP_UTF8,0,s.c_str(),s.size(),&re[0],re.size());   return re;}/// 宽字符串 到 UTF8string wstring_to_utf8( wstring& ws ){   if( ws.empty() ) return "";    int retval = ::WideCharToMultiByte(CP_UTF8,0,ws.c_str(),ws.size(),0,0,0,0);   string re;   re.resize( retval );   ::WideCharToMultiByte(CP_UTF8,0,ws.c_str(),ws.size(),&re[0],re.size(),0,0);   return re;}string wstring_to_utf8( const wchar_t* ws, size_t sz ){   if( ws == NULL || sz == 0 ) return "";   int retval = ::WideCharToMultiByte(CP_UTF8,0,ws,sz,0,0,0,0);   string re;    re.resize( retval );   ::WideCharToMultiByte(CP_UTF8,0,ws,sz,&re[0],re.size(),0,0);   return re;}string from_base64(string &base64){   int nSize = ATL::Base64DecodeGetRequiredLength(base64.size());   byte*  pData = new byte[nSize+1];   ATL::Base64Decode(base64.c_str(), base64.size(), pData, &nSize);   pData[nSize] = 0;   string str = (char *)pData;   delete []pData;   return wstring_to_string(utf8_to_wstring(str));}wstring utf8_to_unicode(const string& utf8string){   int widesize = ::MultiByteToWideChar(CP_UTF8, 0, utf8string.c_str(), -1, NULL, 0);   if (widesize == ERROR_NO_UNICODE_TRANSLATION)   {      throw exception("Invalid UTF-8 sequence.");   }   if (widesize == 0)   {   throw exception("Error in conversion.");   }    vector<wchar_t> resultstring(widesize);    int convresult = ::MultiByteToWideChar(CP_UTF8, 0, utf8string.c_str(), -1, &resultstring[0], widesize);    if (convresult != widesize)   {      throw exception("La falla!");   }    return wstring(&resultstring[0]);}wstring acsi_to_widebyte(string& strascii){   int widesize = MultiByteToWideChar (CP_ACP, 0, (char*)strascii.c_str(), -1, NULL, 0);   if (widesize == ERROR_NO_UNICODE_TRANSLATION)   {      throw exception("Invalid UTF-8 sequence.");   }   if (widesize == 0)   {      throw exception("Error in conversion.");   }   vector<wchar_t> resultstring(widesize);   int convresult = MultiByteToWideChar (CP_ACP, 0, (char*)strascii.c_str(), -1, &resultstring[0], widesize);   if (convresult != widesize)   {      throw exception("La falla!");   }   return wstring(&resultstring[0]);   }   string unicode_to_utf8(const wstring& widestring)   {   int utf8size = ::WideCharToMultiByte(CP_UTF8, 0, widestring.c_str(), -1, NULL, 0, NULL, NULL);   if (utf8size == 0)   {      throw exception("Error in conversion.");   }   vector<char> resultstring(utf8size);   int convresult = ::WideCharToMultiByte(CP_UTF8, 0, widestring.c_str(), -1, &resultstring[0], utf8size, NULL, NULL);   if (convresult != utf8size)   {      throw exception("La falla!");   }    return string(&resultstring[0]);}string ascii_to_utf8(string& strAsciiCode){   string strRet("");   //先把 ascii 转为 unicode   wstring wstr = acsi_to_widebyte(strAsciiCode);   //最后把 unicode 转为 utf8   strRet = unicode_to_utf8(wstr);   return strRet;}int split( const string& str,vector<string>& subs, const char& sep /* = */ ){   string temp = str;   temp += sep;   int count = 0;   size_t pos = temp.find( sep );   size_t from = 0;   while ( pos != temp.npos )   {      string sub_str = temp.substr( from, pos - from );      //if ( sub_str.length() > 0 )     {           ++ count;           subs.push_back( sub_str );     }     from = pos + 1;     pos = temp.find( sep, from );   }   return count;}int splitw( const wstring& str, vector<wstring>& subs, const wchar_t& sep /* = */ ){   wstring temp = str;   temp += sep;   int count = 0;   size_t pos = temp.find( sep );   size_t from = 0;   while ( pos != temp.npos )   {       wstring sub_str = temp.substr( from, pos - from );       //if ( sub_str.length() > 0 )       {           ++ count;           subs.push_back( sub_str );        }        from = pos + 1;        pos = temp.find( sep, from );    }     return count;}///< 字符串替换string& replace_all_s(string& str, const string& old_value,const string& new_value){   while(true)  {       string::size_type pos(0);      if( (pos = str.find( old_value ) )!=string::npos )         str.replace(pos,old_value.length(),new_value);      else         break;  }  return str;}wstring& replace_all_ws(wstring& str, const wstring& old_value,const wstring& new_value){   while(true)   {      wstring::size_type pos(0);      if( (pos = str.find( old_value ) )!=wstring::npos )         str.replace(pos,old_value.length(),new_value);      else         break;   }   return str;}string& replace_all_distinct_s(string& str,const string& old_value,const string& new_value){   for(string::size_type pos(0); pos!=string::npos; pos+=new_value.length())   {         if( (pos=str.find(old_value,pos))!=string::npos )            str.replace(pos,old_value.length(),new_value);         else break;   }   return str;}wstring& replace_all_distinct_ws(wstring& str,const wstring& old_value,const wstring& new_value){   for(wstring::size_type pos(0); pos!=wstring::npos; pos+=new_value.length() )   {      if( (pos=str.find(old_value,pos))!=wstring::npos )         str.replace(pos,old_value.length(),new_value);      else         break;   }      return str;}